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Prenatal sex discernment is the prenatal testing for discerning the sex of a fetus before birth. ==Methods== Prenatal sex discernment can be performed by preimplantation genetic diagnosis before conception, but this method may not always be classified as ''prenatal sex discernment'' because it's performed even before implantation. *Cell-free fetal DNA testing, wherein a venipuncture is performed on the mother to analyze the small amount of fetal DNA that can be found within it. It provides the earliest post-implantation test. A meta-analysis published in 2011 found that such tests are reliable more than 98% of the time, as long as they are taken after the seventh week of pregnancy. *Chorionic villus sampling (CVS) and amniocentesis are two rather invasive testing procedures. These may, in principle, be performed as early as the 8th and the 9th week of pregnancy. The difficulty of these tests and the risk of damage to the fetus, potentially resulting in miscarriage or congenital abnormalities (especially when done early during the pregnancy), make them quite rare during the first trimester. In the United States, CVS and amniocentesis are most commonly performed after the 11th and the 15th week of pregnancy. *Obstetric ultrasonography, either transvaginally or transabdominally, can check for the ''sagittal sign'' as a marker of fetal sex. It can be performed between 65 and 69 days from fertilization (week 12 of gestational age), where it gives a result in 90% of cases - a result that is correct in approximately ¾ of cases, according to a study from 2001. Accuracy for males is approximately 50% and for females almost 100%. When performed later, after 70 days from fertilization (at week 13 of gestational age), it gives an accurate result in almost 100% of cases.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「prenatal sex discernment」の詳細全文を読む スポンサード リンク
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